Motion compensation system for power tong apparatus

ABSTRACT

A power well pipe tong assembly having a back-up tong unit and power tong unit above the back-up unit and interconnected for vertical movement one relative to the other on parallel horizontal planes and a presser device actuated by fluid pressure interposed between the two tong units to counterbalance the weight of the power tong during such vertical movement.

United States Patent [191 Wilms [451 Oct. 1,1974

[ MOTION COMPENSATION SYSTEM FOR POWER TONG APPARATUS [75] Inventor:Carl Alfred Wilms, La Habra, Calif.

[73] Assignee: Byron Jackson Inc., Long Beach,

Calif.

22 Filed: 0a. 18, 1973 211 Appl. No.: 407,698

Related US. Application Data [63] Continuation of Ser. No. 216.182.January 7. 1972, which is a continuation-in-part of Ser. No. 134.552.April 16. 1971. abandoned.

[52] US. Cl 81/5734, 81/57.]6, 173/164 [51] Int. Cl B25b 13/50, E2lb19/16 [58] Field of Search 8l/57.15, 57.16, 57.22,

[56] References Cited UNITED STATES PATENTS 2/1954 Cormany 81/57.l6

2,969,702 1/1961 Cornish 81/57.l6 3,086,413 4/1963 Mason 8l/57.18 X3,288,000 11/1966 F0ster.... ill/57.34 3,518,903 7/1970 Ham 81/57.]6

Primary Examiner-Al Lawrence Smith Assistant Examiner-.1. C. PetersAttorney, Agent, or Firm-John 0. Evans, Jr.

[ 5 7 ABSTRACT A power well pipe tong assembly having a back-up tongunit and power tong unit above the back-up unit and interconnected forvertical movement one relative to the other on parallel horizontalplanes and a presser device actuated by fluid pressure interposedbetween the two tong units to counterbalance the weight of the powertong during such vertical movement.

20 Claims, 13 Drawing'Figures PAIENIEDBBI H 1 3,838,613

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FIG- 11. We

FIG: 12

MOTION COMPENSATION SYSTEM FOR POWER TONG APPARATUS BACKGROUND OF THEINVENTION This application is a continuation of copending applicationSer. No. 216,182, filed Jan. 7, 1972, for Motion Compensation System forPower Tong Apparatus, now abandoned, which application is acontinuation-in-part of application Ser. No. 134,552, filed Apr. 16,1971, for Combined Back Up Tong and Power Tong with Joint MotionCompensation, now abandoned.

In the drilling of well bores, such as oil and gas wells, into the earthand in the periodic round-tripping of the drill string, it is necessaryto make up and break out the tool joints of stands or lengths of drillpipe which together constitute the drill string. As is well known suchtool joints are generally threaded joints consisting of an internallythreaded box on the drill pipe which is disposed in the well bore andsupported in the usual rotary table, and an externally threaded pin onthe length or stand of drill pipe which is being added to or removedfrom the drill string. Such tool joints also generally include radialshoulders on the box and on the pin which engage with one another whenthe joint is tight.

To tightly make up such a tool joint or break out the joint, as the casemay be, requires a substantial force which is applied to the respectivetool joint pin and box sections by rotating the length or stand of drillpipe which is being added or removed, while the drill string in the wellbore is held stationary. To initially shoulder the tool joint or toremove the pin from the box, the rotatable pipe stand is generallyrotated at high speed to save time, per joint, such operation beingreferred to as spinning in or out, as the case may be.

The spinning operation, in any event, involves relative axial movementof the tool joint shoulders into and out of engagement, such axialmovement being caused by the threads on the pin and in the box.

For the purpose of spinning and making up and breaking out tool jointsin well drilling pipe, various power tongs have been heretofore providedand are adapted to grip the tool joint of the length or stand of drillpipe suspended in the derrick and impart rotation thereto. In addition,various back up tongs have been heretofore provided for engaging andholding stationary the tool joint at the upper end of the drill stringwhich is supported in the usual master bushing by wedges or slips whichare movable between pipe supporting and out of the way positions, eithermanually or by power actuated means.

Such operations, using a power tong and a back-up tong, inherentlyrequire that the power tong move towards and away from the back-up tongduring the spinning of the pipe stand being added to or removed from thedrill string, since if such movement cannot take place, then, the tooljoint section engaged by the power tong will be forced to slide relativeto the gripping I means of the power tong or the tongs will berelatively cocked.

THE PRIOR ART A power tong and a back-up tong combination which typifiesthe prior art, is shown and described in US. Pat. No. 3,518,903, grantedJuly 7, 1970, wherein the back-up tong is suspended beneath the powertong, and the power tong is supported by a crane based on the derrickfloor. Springs are interposed between the power tong and the back-uptong, and pin means shiftably supports the back-up tong beneath thepower tong.

Such power tongs are also disclosed, for example, in the US. patentapplications of Bela Geczy et a1, filed Apr. 16, 1971, Ser. No. 134,554,for Chain Driven Spinning Make Up and Break Out Tongs, now US Pat. No.3,691,875, issued Sept. 19, 1972; and Carl A. Wilms, filed Apr. 16,1971, Ser. No. 134,553, for Chain Actuated Pipe Tongs. The disclosuresof these identified patent applications are specifically incorporatedherein by reference.

SUMMARY OF THE INVENTION The present invention provides a power tong andback-up tong combination wherein the respective tongs are interconnectedfor relative vertical movement on planes normal to the direction ofrelative movement of the tool joint parts when they are being made up orbroken out, whereby relative cocking of the tongs on either tool jointsection is prohibited.

In addition, the present invention provides such a combination in whichthe back-up tong is supported or suspended above the derrick floor andthe power tong is supported on the back-up tong by means whichessentially counterbalance the weight of the power tong, so that thelatter is easily movable vertically as a result of spinning of the pipestand by the power tong, which spinning results in upward or downwardmovement of the power tong due to the progressive disengagement orengagement of the complemental threads of the pin and box sections ofthe tool joint.

More particularly, the present invention provides fluid pressurecontaining means or presser means acting between the back-up tong andthe power tong in such a manner that the weight of the power tong may besubstantially nullified. For example, when the tong combination is beingemployed to make up tool joints, under which circumstances the powertong must be in a starting position spaced upwardly from the back-uptong, the fluid pressure containing or presser means may over compensatefor the weight of the power tong to a slight extent, so that as the tooljoint spins up, the power tong is easily moved downwardly. On the other'hand, for example, when the tong combination is being employed to breakout tool joints, under which circumstances the power tong must be in itslower starting position, the presser means may compensate for slightlyless than the weight of the power tong, so that the power tong is easilymoved upwardly as the tool joint is being spun out.

In accomplishing the foregoing, the objectives of the invention includethe provision of a power tong and back up tong combination which issimple in its construction, durable, and easy to control and operate.

This invention possesses many other advantages, and has other purposeswhich may be made more clearly apparent from a consideration of theforms in which it may be embodied. These forms are shown in the drawingsaccompanying and forming part of the present specification. They willnow .be described in detail, for the purpose of illustrating the generalprinciples of the invention; but it is to be understood that suchdetailed description is not to be taken in a limiting sense.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of a powertong and back-up tong combination made in accordance with the inventionand supported above the floor of a drilling derrick, and showing a drillstring and a pipe stand in the relatively unthreaded positions;

FIG. 2 is a top plan of the combination of FIG. 1;

FIG. 3 is a side elevation of the power tong and backup tong of FIG. 1,but showing them in a position at which the tool joint is shouldered;

FIG. 4 is a detail view in vertical section, through a typical connectorpin assembly, as taken on the line 44 of FIG. 2;

FIG. 5 is a detail view in vertical section through the fluid pressurecontaining means and portions of the tongs, as taken on the line 55 ofFIG. 2;

FIG. 6 is an elevational view of an alternate embodiment of the presentinvention;

FIG. 7 is a partially cut away planview taken along the line -77 of FIG.6;

FIG. 8 is a sectional view of an alternate embodiment of the fluidpressure containing means or presser means as taken along the line 88 ofFIG. 7;

FIG. 9 is a partly sectional elevational view taken along the line 9-9of FIG. 6;

FIG. 10 is a partially sectional elevational view taken along the linel010 of FIG. 9;

FIG. 11 is a sectional view taken along the line 11l1 of FIG. 10;

FIG. 12 is a sectional view taken along the line 1212 of FIG. 6; andFIG. 13 is a schematic illustration of the presser means and anadjustable pressure system for use with the same.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As seen in FIGS. 1, 2, 3, 6 and7 of the drawings, the power tong and back-up tong combination BT of thepresent invention generally comprises a back-up tong assembly B and apower tong assembly T, support means S for the back-up tong B, aplurality of connector means C enabling relative movement of the tongs Tand B toward and away from one another, and presser means or fluidpressure containing means P interposed between the tongs T and B andoperable to more orless counterbalance the weight of the power tong T toallow the latter to move downwardly during the make up of a tool joint Jand upwardly during the break out of the tool joint J in the drill pipeDP.

The power tong T may be of any type, including by way of example, thatshown and described in detail in the aforementioned U.S. Pat. No.3,518,903 and U.S.

patent disclosures. Likewise, the back-up tong B may be of any type,including by way of example, that shown and described in said patent andpatent disclosures. Such tongs are well known in the art and withoutrequiring detailed illustration and description herein will beunderstood to be used, when supported in the usual derrick or on thederrick floor, to thread the pin end 1 of the tool joint J into the boxend 2, from the positions shown in FIG. 1 to the position shown in FIG.3, at which the joint .I is tightly shouldered, when making up joints,or to unthread the pin 1 from the box 2 when the joint J is being brokenout. During such operations, the box end 2 is held against rotation inthe back-up tong B, while rotation of the pin end 1 is effected by thepower tong T. Since both tongs tightly grip the tool joint parts, it isnecessary that the power tong T move between the elevated position,spaced above the back-up tong B, as seen in FIG. 1, and the lowerposition, as seen in FIG. 3, the distance between these two positionsbeing equal to the axial movement of the pin 1 caused by the threads asthe joint J is made up and broken out.

In order to rotate the pin end 1 of the joint J. the power tong,generally, comprises gripping jaws 4 which are actuated from retractedpositions to gripping positions, as seen in FIG. 2, and the pin end 1 isthen revolved by a suitable power source, such as a hydraulic motor Mthrough suitable gearing (not shown) in a housing 5 on the power tongbody 6. A similar jaw system (not shown) is typically included in theback-up tong- B, but the jaws are held against revolution when actuatedinto engagement with the box end 2 of the joint J. As previouslyindicated the details of the tongs T and B may vary, and examplesincluding gripping jaws and operating means therefor, are abundantlyillustrated in the above-identified U.S. patent and are otherwise wellknown.

In order to support the drill pipe in the well bore, with the upper endor box 2 disposed, as seen in FIG. 1, in position for grippingengagement by the back-up tong B, suitable slip mechanism, say a powerslip apparatus PS is supported on the derrick floor F and is operable toreleasably engage the pipe below the box end 2, so that the drill pipestring is suspended in the well from the usual rotary table R, all as iswell known.

The supporting means S previously referred to may take any convenientform, such as the customary cable support by which the tong combinationis suspended from the derrick in a horizontal disposition and steadiedby a stiff arm or other supporting means such as a pedestal or carriageof the nature shown in FIG. 6. In FIG. 1 the supporting means is shownas being of the suspended type. More particularly, a U-shaped member oryoke 10 is shown as straddling the power tong T and being connected bysuitable fasteners 11 to the body of the back-up tong B, the connectionbeing obviously the same at both sides. The bight portion 12 of the yoke10 has a centrally located, upstanding ear 13 adapted to be connected toa clevis 14 at the lower end of a supporting cable 15 which will beunderstood to extend upwardly to a suitable connection (not shown) withhoist mechanism which may be employed to adjust the elevation of thetong combination with respect to the derrick floor F and thus the box 2of the drill pipe. In addition, a stiff arm 16 is generally illustratedas being connected to one side of the tong combination adjacent the endremote from the pipe DP to stabilize the combination and provide asafety means to prevent reactive torque from causing the tongcombination-to swing about the drill pipe DP if the power tong T isoperated without gripping the box 2 with the back-up tong B. Otherwise,when the back-up tong is gripping the box 2 the reaction torque is takenby the connector means C.

These connector means C are conveniently located, preferably adjacent tothe ends of the tong combination and, as previously indicated, functionto interconnect the power tong T with the back-up tong B in such amanner that the power tong is vertically shiftable relative to theback-up tong, between the positions shown in FIGS. 1 and 3, in parallelrelation to the back-up tong. In other words, the two tongs arehorizontally extended on parallel planes and are vertically movable, onerelative to the other, and the connector means C constrain the tongs tosuch movement.

As seen in FIG. 2, the connector means as illustrated are triangularlyrelated with a pair of connector means at opposite forward corners ofthe tong combination and a third connector means at the rear or otherend of the combination. A typical connector means C for the embodimentshown in FIGS. 1 and 2 is best illustrated in FIG. 4. The tong T has anear providing a bore 21 in which a connector pin 22 is suitably affixed,the lower portion of the pin 22 extending downwardly and slidablythrough a bushing 23 which is affixed in a bore 24 provided in an ear 25on the tong B. At its lower end, the pin 22 has a keeper in the form ofa washer 26 secured by a fastener 27 to the pin 22 and having a diametersuch that the washer will abut beneath the ear 25 to limit upwardmovement of the tong T.

It will now be understood that with the structure thus far described,the two tongs T and B are free to move relatively vertically whilesuspended by the supporting means S. Such vertical movement is necessarywhen the joint parts 1 and 2 of the joint J are being threaded in orout, to compensate for the relative axial movement of the joint parts 1and 2, without causing longitudinal slippage of the tong gripping meanson the joint parts 1 and 2. The connector means C hold the tongs T and Bin parallel relation.

However, the power tong T is typically quite heavy, and therefore thepresser means P previously referred to is provided to more or lesscounterbalance the weight of the power tong T to relieve the pipegripping means from the load of the tong T.

The fluid pressure containing means P as illustrated in FIG. 5 comprisesa presser bladder 30 of generally flat, circular form, interposedbetween the bottom wall 31 of the power tong T and the top wall 32 ofthe backup tong B. In the illustrated embodiment, the bladder seats in acomplemental cavity 33 in the wall 32 of the back-up tong.

The presser bladder 30 is composed of elastomeric material and may besuitably reinforced against rupture or other failure. Centrally of thebottom wall 34 of the bladder 30 is a sleeve 35 which is suitably bondedin an opening 36 in the bladder wall 34 and adapted to extend downwardlyinto an opening 37 in the tong wall 32 and onto a cylindrical neck 38 ofa fluid pressure inlet fitting 39 which is suitably affixed beneath thetong wall 32, as by welding at 40. Suitable seal means 41 are providedbetween the opposing cylindrical surfaces of the sleeve 35 and the neck38, and fluid conduit 42 is connected to the fitting 39 so that fluidmay be supplied to the interior of the presser bladder 30 at a selectedand regulated pressure as will be later described.

Since the purpose of the presser bladder 30 is to more or lesscounterbalance the weight of the tong T, to .facilitate its movementvertically during the making up and breaking out of pipe joints 1,counterbalance presser means P is preferably located beneath the powertong T or applies lift to the tong T substantially at the center ofgravity of the tong T which of course varies from power tong to powertong. In addition, while a bladder is illustrated as a simple,relatively inexpensive yet effective counterbalance device, it will beunderstood that other fluid pressure responsive presser devices as laterdescribed, are also applicable, the essential point being that theweight of the power tong is more or less counterbalanced as it movesupwardly or downwardly with the pin end or joint part 1 during thebreaking out and making up of the joints J, so that the weight of thepower tong T is not applied to the pipe gripping means or jaws 4 of thepower tong T.

FIGS. 6-12 illustrate an alternate embodiment of the invention whereinthe same indicia are assigned to components corresponding to those aspreviously described. The alternate embodiment as illustrated in FIGS.6, 7 and 8 includes positioning apparatus having a vertically disposedcolumn 76 formed of a web joined between two parallel flanges such as anI-beam, for example. Upper upper support 78 is connected with the top ofcolumn 76 as by bolted connection as shown, for example. Ypper support78 is connected to a pivotable upper bearing unit 80 shown in FIG. 6. Alower support is connected to a pivotable lower bearing unit (not shown)in turn attached to a derrick floor. An alternate tong support means Sis mounted in cantilever fashion from column 76 as before described.

A generally hollow and elongated rectangular support collar 82 ofsupport means S is fitted about column 76 and adapted to be moved up anddown along column 76. Collar 82 is maintained and rigidly supported inlongitudinal movable alignment with column 76 by a roller assembly 84incorporated within collar 82. As shown, a plurality of flanged rollers86 are included in assembly 84 and mounted to abut and roll along theinner faces of the flanges of column 76 with the roller flanges abuttingthe side edges of the column flanges to restrain collar 82 in fixedhorizontal or lateral relation with respect to the column.

A tong support yoke structure 88 is mounted to collar 82 and projectshorizontally and radially from the pivotable axis of column 76. A powerpipe tong assembly BT adapted to receive a well pipe DP and including aback-up tong B and a rotating power tong T is mounted within yoke 88through a cradle assembly having cradle units 90 and 90' comprising partof connector means C. For the purpose of this description, the powertong assembly BT may be considered to be of construction such asdisclosed in the previously referenced US. patent disclosures, forexample.

Mounted in generally upright posture adjacent column 76 is a powersource adapted for linear movement which is provided as a hydraulicpiston and cylinder unit 92. As later described, power source 92 ispivotally mounted at its lower end to the lower end of column 76 (notshown) and terminates at its upper movable end with a force and movementcrosshead unit 94. Flexible force and movement transfer means areprovided as a pair of roller chains 96 (only one shown) which strad-.

dle power source 92 and which are respectively meshed across chainsprockets incorporated as part of crosshead unit 94. Chains 96 are alsorespectively anchored at their lower ends to the lower end of column 76(not shown) and extend upwardly over crosshead unit 94 to a positionbelow unit 94 where such chains are respectively anchored to yokestructure 88.

Upper support assembly 78 is removably attached to column 76 throughprovision of downwardly projecting flanges 98 which are respectivelyconnected to the flanges of column 76 by means of bolts 100. Uppersupport member 78 is provided as removable to permit assembly of supportcollar 82 as shown in FIG. 6. Upper bearing unit 80 is a flanged ballbearing assembly connected to support 78 and to a cylindrical retainingbitt 102 by means of fasteners (not shown). Bitt 102 is equipped with aplurality of lobed and divided retainer rings such as indicated at 106and 108. Rings 106 and 108,are assembled with fasteners such as capscrews 110, for example. Horizontal tie bars 112 and 114 arerespectively connected to the lobes of rings 106 and 108 through clevisand pin arrangements 116 and 118. The other ends of tie bars 112 and 114are connected in tension to the structure (not shown) of the wellderrick. To be noted is that more than the two disclosed tie bars may beutilized as desired to provide appropriate horizontal stability in aparticular installation.

The alternate embodiment of presser P is best shown in FIGS. 7 and 8 toinclude a movable piston 60 including an externally mounted slidingbearing sleeve 62 and a'fluid pressure seal means such as seal rings 64interposed snugly and reciproeably fitted-within a cylinder 66. As showncylinder 66 is firmly supported from the bottom wall of back-up tong Bthrough support webs 68 connected to such bottom wall as by welding andconnected in fluid sealed relation to the closed end of cylinder 66 bymeans of fasteners such as cap screws 70 and seal washers or gaskets 72as shown. The upper open end of cylinder 66 extends through a holedefined in the top wall 32 of the tong B. A seal ring 74 is interposedbetween cylinder 66 and the hole in tong wall 32 to maintain theinterior of tong B free of dirt and detritus as might entertherebetween.

As shown, fluid pressure entering cylinder 66 will cause upward movementof piston 60 into abutting contact with bottom wall 31 of rotating powertong T. The pressing force of presser P to counterbalance tong T aspreviously described is. thereon commensurate with the fluid pressureapplied through conduit 42, as later described. Of note is that the faceof piston 62 which abuts the bottom wall'3l of tong T is provided topermit free horizontal sliding contact between the piston face and suchbottom wall, such horizontal movement being limited by the embodimentsof connector means C as heretofore described with reference to FIGS. 1-4and hereafter described with reference to FIGS. 612.

Yoke 88 (FIGQ6) of support means S includes a clevis box 120 mounted atthe upper part of a load plate 122 comprising part of collar 82 andsupport arms 124 and 124' mounted to and projecting from the lower partof load plate 122. Support cradles 90 and 90' are respectively mountedto arms 124 and 124, as later described with reference to FIGS. -12, andsecured through pinned connection to members 126 and 126' of a supportfork 128 to clevis box 120. Clevis box 120 defines a cavity which willreceive chain crosshead 94 and is provided with a chain anchor bracket130 to which chains 96 are secured by bolted connection as shown in FIG.6. Support means S also includes a torque section alignment pin 188projecting from backup tong B and received in a hole defined in rotatingpower tong T as shown in FIGS. 6 and 7. The installation' of alignmentpin 188 may be similar to an inverted arrangement of FIG. 4 withoutprovision of washer 26 as shown.

Power source 92 as provided includes a piston and cylinder unit having acylinder 132 with a piston rod 134 extending from the cylinder. Chaincrosshead 94 is mounted to the distal end of rod 134 and cylinder 132 ispivotally mounted to the lower end of column 76 (not shown). Cylinder132 is equipped with a fluid fitting (not shown) through which fluidsunder pressure may be forced into or discharged from the cylinder tocause extension and retraction of piston rod 134 with correspondingperpendicular movement of support yoke 88 as previously described.Though compressible fluids such as air may be used, incompressiblehydraulic fluids such as oil is preferred in the operation of powersource 92.

FIGS. 6, 7 and 9-11 show the supporting cradle including cradle unitsand 90'. Cradle unit 90' is .provided of construction which is in mirrorimage of the construction of cradle unit 90 and accordingly need not bedescribed in detail. FIGS. 10, 11 and 12 best show the details of cradleunit 90. Cradle unit 90 generally includes a supporting guide 136 formedat the extremity of support arm 124. which guides and supports a tongunit carrier frame 138 in pivoting and raidally movable relation througha roller unit 140 as shown.

Supporting guide 136 is formed of generally rectangular configurationwith a pair of upwardly extending ears which form a clevis 142 forattachment by means of a pin to support fork 128. Parallel trackways 144are horizontally and radially defined within guide 136 and closed at thedistal end of support arm 124 by a closure bar 146 connected across thetrackways to guide 136 by fasteners such as cap screws 148 as shown. Aflanged guide block 150 is snugly fitted in sliding relation withintrackways 144 with the flanges of the guide block abutting the sides ofthe trackways and maintaining the guide block in radial alignment withsupport arm 124. Adjustable radial support of guide block 150 isprovided by a threaded stud 152 projecting from the guide blocks througha hole in closure bar 146 with threaded lock nuts 154 adjustablythreaded on stud 152 and tightened to lock on either side of bar 146. Ashort machined slot 156 having circular ends is horizontally defined inguide block 150 which slot receives roller 140 and permits limitedradial movement of the roller within the slot for purposes laterdescribed. Roller 140, as disposed within slot 156, is secured by meansof a pin to a clevis 158 formed as an upper part of carrier frame 138 ina manner as shown to cause carrier frame 138 to be suspended in pivotedand radially movable relation through roller 140 from guide block 150.

Carrier frame 138 is adapted to be rigidly connected to pipe back-upunit B by fasteners such as cap screws 160 to support lugs 162 whichproject from unit B as shown. As shown, four guide rollers 164 aremounted in rectangular formation on carrier frame 138 by means of pinsto accommodate a guide bar 166 and maintain the guide bar in verticallymovable alignment. Guide bar 166 is adapted to be rigidly connected bymeans of fasteners such as cap screws 168 to pipe rotating power unit Tas shown.

Vertical movement of pipe rotating unit T relative to pipe back-up unitB is maintained within a predetermined limit by means of a dog 170 whichis connected to and projects from guide bar 166 into a limit slot 172defined in carrier frame 138 as shown.

The construction of cradle unit 90 as shown provides parallel alignmentand limited vertical movement between rotating unit T and back-up unit Bwhile permitting adjustable limited radial movement and verticalpivoting of the entire power tong assembly ET. The

limited radial movement of carrier frame 138 as provided by movement ofroller unit.140 within slot 156 permits slight radial movement of powertong assembly BT with respect to column 76 to compensate forcorresponding horizontal deviations of the well pipe within the wellbore. Initial radial range adjustment is provided by adjustment of guideblock 150 through positioning of adjustment stud 152.

Pivotal movement or rocking of power tong assembly BT about the axis ofroller unit 140 is resiliently limited by a stabilizing unit 174 and174', shown in FIGS. 6, 7 and 12. Only unit 174 needs to be described asa flanged bracket 176 extending inwardly and downwardly from support arm124 of yoke 88. A bolt 178 extends upwardly through a lug 180 projectingfrom back up tong B and through a flange 182 projecting from bracket 176and is secured in position by adjustable lock nuts 184.,A pair ofresilient coil springs 186 are disposed between lug 180, the flange 182and lock nuts 184 as shown. The bolt is fitted through lug 180 andflange 182 sufficiently loosely to permit the radial movement of tongassembly BT as previously described. Such construction provides firm yetresilient vertical support of tong assembly BT against movement aboutthe axis of roller unit 140. Such resilience permits compensation forminor deviations from a vertical position of the well pipe DP extendingthrough tong assembly BT.

Referring to FIG. 13, an exemplary fluid pressure control system isshown, whereby the presser bladder 30 of the fluid pressurecounterbalancing means is maintained at a selected pressure during makeup and break out of joints J. In this schematic system, it will be notedthat a pneumatic system is shown, for example, and the conduit 42 whichis connected to the presser bladder 30 is selectively connectable to anair source conduit 50 by a suitable selector valve SV and either of apair of variable pressure regulators consisting of a joint break-outregulator RB and a joint make-up regulator RM.

Valve SU may be of any desired type and is simply shown as a manuallyactuated detented, two position valve, but in automated systems, thevalve SV, obviously, may be pilot operated. In any event,in oneposition, as shown in FIG. 6, the valve SV connects the bladder conduit42 with a conduit 51 which leads from the regulator RB to the valve SVso that the pressure in the presser bladder 30 is determined by thesetting of the adjustable regulator RB; and in the other position of thevalve SV, the bladder conduit 42 will be connected with a conduit 52which leads from the regulator RM to the valve SV, so that the pressurein the bladder 30 will be determined by the setting of the adjustableregulator RM.

To properly counterbalance the weight of the power tong T during jointbreak out operations, as illustrated in FIG. 6, the regulator RB isadjusted so that the force derived from the presser bladder 30 due tointernal pressure preferably is slightly less than the weight of tong Tso that the power tong T will be initially lowered to the startingposition of FIG. 3 and as the joint part 1 moves upwardly from the jointpart 2, from the position of FIG. 3 to the position of FIG. 1, the powertong T easily moves correspondingly. As previously indicated, suchmovement occurs only in parallel planes due to the restraint of theconnector means C against cocking of the tongs, one relative to theother. On the other hand, when the tong combination is being employed injoint make up operations, and the valve SV is in the alternate positionfrom that shown, the regulator RM is adjusted so that the force derivedfrom the presser bladder 30 due to internal pressure preferably isslightly greater than the weight of the power tong T,

so that the tong T will be initially in the upper position of FIG. 1spaced from the'back-up tong B, but when the jaws 4 grip the tool jointpart 1 to spin the latter into the joint part 2, the tong T is easilymoved downwardly as the joint J isprogressively made up.

From the foregoing it will be apparent that the present inventionprovides a simple solution to the problem of relative tong movement whenthreaded tool joints of drill pipe are being made up and broken' out.While reference herein to the tool joints of drill pipe has been usedfor purposes of disclosing the invention in the environment of its mainutility in the well drilling and completion field, it will be understoodthat the invention may also be availed of in other applications, such asmaking up casing couplings, if desired, or otherwise,

- where the relative movement of one joint part and another isencountered.

The foregoing description and drawing will suggest other embodiments andvariations to those skilled in the art, all of which are intended to beincluded in the spirit of the invention as herein set forth.

What is claimed is: e

1. Pipe tong apparatus comprising: a power tong assembly including apipe back-up tong unit disposed in horizontally parallel relation belowa pipe rotating power tong unit, and presser means interposed betweensaid tong unit to apply separating force between said tong units tosubstantially counterbalance the weight of said power tong unit as saidpower tong unit is vertically moved with respect to said back-up tongunit, said counterbalance means comprising a bladder interposed betweensaid tong means, and means for supplying fluid under pressure to saidbladder, said bladder acting on said power tong means to apply saidforce.

2. A tong assembly comprising: back-up tong means for holding a firstpipe against rotation, power tong means for rotating a second pipe, saidpipes having complementally threaded joint parts engageable anddisengageable upon rotation of said second pipe, connector meansinterconnecting said tong means for movement only toward and away fromone another responsive to threaded engagement and disengagement of saidjoint parts, and presser means interposed between said tong means toapply a force to separate said tong means, whereby to substantiallycounterbalance the weight of said power tong means when said back-uptong means is supported in a horizontal plane and said pipe is disposedvertically, wherein said presser means comprises a bladder between saidtongs.

3. Pipe tong apparatus comprising: a power tong assembly including apipe back-up tong unit disposed in horizontally parallel relation with apipe rotating power tong unit; a vertically disposed support columnprovided with lower bearing means adapted to be mounted to a fixedsupport in a well derrick and upper bearing means adapted to beconnected to the structure of the derrick to provide vertical andhorizontal support for said column while permitting said column to pivothorizontally; a vertically movable support collar fitted about saidcolumn and supported in alignment for movement up and down said column;a pipe tong support yoke means rigidly mounted to said support collar atits first end to extend horizontally and radially pivotable from saidsupport column; said yoke structure being adapted to receive and supportsaid power tong assembly through a supporting cradle means mounted tothe second end of said yoke; and presser means interposed between saidtong units to apply separating force between said tong units tosubstantially counterbalance the weight of said power tong unit throughvertical movement of said power tong unit, including a power sourceproviding linear movement mounted in upright position adjacent saidcolumn with its lower end mounted to the lower end of said column andits upper end connected through a flexible force transfer means to saidsupport yoke, said flexible force transfer means being anchoredrelatively between said yoke structure and said support column and beingconnected across a force transfer crosshead means mounted to the upperend of said power source.

4. Pipe tong apparatus comprising: a power tong assembly including apipe back-up tong unit disposed in horizontally parallel relation with apipe rotating power tong unit; a vertically disposed support columnprovided with lower bearing means adapted to be mounted to a fixedsupport in a well derrick and upper bearing means adapted to beconnected to the structure of the derrick to provide vertical andhorizontal support for said column while permitting said column to pivothorizontally a vertically movable support collar fitted about saidcolumn and supported in alignment for movement up and down said column;a pipe tong support yoke means rigidly mounted to said support collar atits first end to extend horizontally and radially pivotable from saidsupport column; said yoke structure being adapted to receive and supportsaid power tong assembly through a supporting cradle means mounted tothe second end of said yoke; and presser means interposed between saidtong units to apply separating force between said tong units tosubstantially counterbalance the weight of said power tong unit throughvertical movement of said power tong unit, wherein said cradle meansincludes means providing resiliently pivoted vertical support of saidback-up tong unit in parallel relation to said yoke structure andproviding support with limited vertical and radial movement of saidpower tong unit with respect to said back-up tong unit and to saidsupport yoke.

5. The positioning apparatus of claim 3, wherein said flexible forcetransfer means includes chain means an chored to the lower end of saidsupport column and to said support yoke and said force transfercrosshead means includes chain sprocket means.

6. The positioning apparatus of claim 3, wherein said cradle meansincludes means providing resiliently pivoted vertical support of saidback-up unit in parallel relation to said yoke structure and providingsupport with limited vertical and radial movement of said rotating unitwith respect to said back-up unit and to said support yoke.

7. The positioning apparatus of claim 3, wherein said power sourcecomprises a piston and cylinder unit having a piston rod connected tosaid force transfer crosshead means.

8. Th positioning apparatus of claim 7 including bydraulic fluid powermeans for actuating said piston and cylinder unit.

9. Pipe tong apparatus comprising: a power tong assembly including apipe back-up tong unit disposed in horizontally parallel relation with apipe rotating power tong unit; a vertically disposed support columnprovided with lower bearing means adapted to be mounted to a fixedsupport in a well derrick and upper bearing means adapted to beconnected to the structure of the derrick to provide vertical andhorizontal support for said column while permitting said column to pivothorizontally; a vertically movable support collar fitted about saidcolumn and supported in alignment for movement up and down said column;a pipe tong support yoke means rigidly mounted to said support collar atits first end to extend horizontally and radially pivot able from saidsupport column; said yoke structure being adapted to receive and supportsaid power tong assembly through a supporting cradle means mounted tothe second end of said yoke; and presser means interposed between saidtong units to apply separating force between said tong units tosubstantially counterbalance the weight of said power tong unit throughvertical movement of said power tong unit, said presser means comprisinga bladder interposed between said tong means, and means for supplyingfluid under pressure to said bladder, said bladder acting on said powertong unit to apply said force.

10. A pipe tong assembly for making up or breaking out threaded jointsin well pipe comprising a horizontally disposed back-up tong unitengageable with a vertically disposed, first threaded pipe joint part tohold I said part and said back-up tong unit against rotation and againstvertical movement relative to each other, means for supporting saidback-up tong unit in a selected vertical position upon a stationarybase, a power tong unit disposed above said back-up tong unit andengageable with a second complementally threaded pipe joint part that isaligned with said first threaded pipe joint part for rotating saidsecond threaded pipe joint part into or out of threaded engagement withsaid first threaded pipe joint part while holding said second threadedpipe joint against vertical movement relative to said power tong unit,and vertically expandable and contactible counterbalance means carriedby said back-up tong unit and associated with said power tong unit foryieldably supporting said power tong unit upon said back-up tong unitfor vertical movements with respect to said back-up tong unit, saidcounterbalance means being constructed and arranged to apply an upwardforce to said power tong unit substantially equal to the weight of saidpower tong unit as said power tong unit is vertically moved in responseto thethreading of said second threaded pipe joint part into or out ofthreaded engagement with said first threaded pipe joint part, saidcounterbalance means being the sole means for vertically supporting saidpower tong unit, said counterbalance means comprising a bladderinterposed between said back-up tong unit and said power tong unit, andmeans for supplying fluid under pressure to said bladder, said bladder.acting on said power tong unit to apply said upward force.

11. A pipe tong assemblyfor making up or breaking out threaded joints invertically disposed well pipe comprising: a base member; a back-up tongunit; means for mounting said back-up tong unit on said base member andin horizontal disposition, and for vertical movement and also forhorizontal movement with respect to said base member; a power tong unit;means for mounting said power tong unit on and superjacent to saidback-up tong unit and in horizontal disposition, and for limitedvertical movements with respect to said backup tong unit; said back-uptong unit having means releasably engageable with a vertically disposed,lower threaded pipe joint part to hold said part and said backup tongunit against relative rotation and vertical movement therebetween; saidpower tong unit having means releasably engageable with an uppercomplementally threaded pipe joint part that is aligned with said lowerthreaded pipe joint part for rotating said upper threaded pipe jointpart into and out of threaded engagement with said lower threaded pipejoint part while holding said upper pipe joint part and said power tongunit against relative vertical movement therebetween; counterbalancemeans including vertically expandable and contractible means carried bysaid back-up tong unit, positioned between said back-up tong unit andsaid power tong unit, and yieldably supporting said power tong unit forvertical movements with respect to said back-up tong unit, saidcounterbalance means being constructed and arranged to apply an upwardforce to said power tong unit substantially equal to the weight thereofas said power tong unit is vertically moved with respect to said back-uptong unit in response to the threading of said upper threaded pipe jointpart into and out of threaded enagement with said lower threaded pipejoint part; and connector means interconnecting said power tong unit andsaid back-up tong unit constraining said power tong unit to movehorizontally with said back-up tong unit as the latter is movedhorizontally with respect to said base member.

12. A pipe tong assembly as defined in claim 11, wherein said means formounting said back-up tong unit on said base member includes pivot meanshaving a vertical pivot axis for horizontal pivotal movement of saidback-up tong unit with respect to said base member.

13. A pipe tong assembly as defined in claim 11, wherein said verticallyexpandable and contractible means comprises pneumatically expandable andcontractible means.

14. A pipe tong assembly as defined in claim 1 1, said verticallyexpandable and contractible means being disposed substantially at thecenter of gravity of said power tong unit.

15. A pipe tong assembly as defined in claim 11, said verticallyexpandable and contractible means comprising a bladder interposedbetween said back-up tong unit and said power tong unit, and means forsupplying fluid under pressure to said bladder, said bladder acting onsaid power tong unit to apply said upward force.

16. A pipe tong assembly as defined in claim 11, said verticallyexpandable and contractible means comprising a piston and cylinder meansinterposed between said back-up tong unit and said power tong unit, saidpiston and cylinder means acting on said power tong unit to apply saidupward forcev 17. A pipe tong assembly as defined in claim 11, whereinsaid connector means also constrains said power tong unit to movevertically towards and away from said back-up tong unit only on parallelplanes.

18. A pipe tong assembly as defined in claim 17 including keeper meansfor limiting movement of said power tong unit away from said back-uptong unit to a location at which said tong units both engage said jointparts when said joint is to be made up.

19. A pipe tong assembly as defined in claim 11, wherein said verticallyexpandable and contractible means comprises pressure fluid containingmeans, said counterbalance means including a make up pressure regulatorand a break out pressure regulator for maintaining selected constantpressures in said pressure fluid containing means and to respectivelymaintain said upward force slightly greater than the weight of saidpower tong unit during the making up of said joints and slightly lessthan the weight of said power tong unit during the breaking out of saidjoints, and means including selector valve means for selectivelycommunicating said regulators with said pressure fluid containing means.

20. Pipe tong apparatus comprising: a power tong assembly including apipe back-up tong unit disposed in horizontally parallel relation belowa pipe rotating power tong unit, presser means interposed between saidtong units to apply separating force between said tong units tosubstantially counterbalance the weight of said power tong unit throughvertical movement of said power tong unit with respect to said back-uptong unit; a vertically disposed support column provided with lowerbearing means adapted to be mounted to a fixed support in a well derrickand upper bearing means adapted to be connected to the structure of thederrick to provide vertical and horizontal support for said column whilepermitting said column to pivot horizontally; a vertically movablehollow support collar fitted about said column and supported inalignment for movement up and down said column by roller means rigidlymounted with said roller and mounted in rolling contact with saidcolumn; a pipe tong support yoke means rigidly mounted to said supportcollar at its first end to extend horizontally and radially pivotablefrom said support column; said yoke structure being adapted to receiveand support said power tong assembly through a supporting cradle meansmounted to the second end of said yoke; a power source providing linearmovement mounted in upright position adjacent said column member withits lower end mounted to the lower end of said support column and itsupper end connected through a flexible force transfer means to saidsupport yoke, said flexible force transfer means being anchoredrelatively between said yoke structure and said support column and beingconnected across a force transfer crosshead means mounted to the upperend of said power source.

1. Pipe tong apparatus comprising: a power tong assembly including apipe back-up tong unit disposed in horizontally parallel relation belowa pipe rotating power tong unit, and presser means interposed betweensaid tong unit to apply separating force between said tong units tosubstantially counterbalance the weight of said power tong unit as saidpower tong unit is vertically moved with respect to said back-up tongunit, said counterbalance means comprising a bladder interposed betweensaid tong means, and means for supplying fluid under pressure to saidbladder, said bladder acting on said power tong means to apply saidforce.
 2. A tong assembly comprising: back-up tong means for holding afirst pipe against rotation, power tong means for rotating a secondpipe, said pipes having complementally threaded joint parts engageableand disengageable upon rotation of said second pipe, connector meansinterconnecting said tong means for movement only toward and away fromone another responsive to threaded engagement and disengagement of saidjoint parts, and presser means interposed between said tong means toapply a force to separate said tong means, whereby to substantiallycounterbalance the weight of said power tong means when said back-uptong means is supported in a horizontal plane and said pipe is disposedvertically, wherein said presser means comprises a bladder between saidtongs.
 3. Pipe tong apparatus comprising: a power tong assemblyincluding a pipe back-up tong unit disposed in horizontally parallelrelation with a pipe rotating power tong unit; a vertically disposedsupport column provided with lower bearing means adapted to be mountedto a fixed support in a well derrick and upper bearing means adapted tobe connected to the structure of the derrick to provide vertical andhorizontal support for said column while permitting said column to pivothorizontally; a vertically movable support collar fitted about saidcolumn and supported in alignment for movement up and down said column;a pipe tong support yoke means rigidly mounted to said support collar atits first end to extend horizontally and radially pivotable from saidsupport column; said yoke structure being adapted to receive and supportsaid power tong assembly through a supporting cradle means mounted tothe second end of said yoke; and presser means interposed between saidtong units tO apply separating force between said tong units tosubstantially counterbalance the weight of said power tong unit throughvertical movement of said power tong unit, including a power sourceproviding linear movement mounted in upright position adjacent saidcolumn with its lower end mounted to the lower end of said column andits upper end connected through a flexible force transfer means to saidsupport yoke, said flexible force transfer means being anchoredrelatively between said yoke structure and said support column and beingconnected across a force transfer crosshead means mounted to the upperend of said power source.
 4. Pipe tong apparatus comprising: a powertong assembly including a pipe back-up tong unit disposed inhorizontally parallel relation with a pipe rotating power tong unit; avertically disposed support column provided with lower bearing meansadapted to be mounted to a fixed support in a well derrick and upperbearing means adapted to be connected to the structure of the derrick toprovide vertical and horizontal support for said column while permittingsaid column to pivot horizontally a vertically movable support collarfitted about said column and supported in alignment for movement up anddown said column; a pipe tong support yoke means rigidly mounted to saidsupport collar at its first end to extend horizontally and radiallypivotable from said support column; said yoke structure being adapted toreceive and support said power tong assembly through a supporting cradlemeans mounted to the second end of said yoke; and presser meansinterposed between said tong units to apply separating force betweensaid tong units to substantially counterbalance the weight of said powertong unit through vertical movement of said power tong unit, whereinsaid cradle means includes means providing resiliently pivoted verticalsupport of said back-up tong unit in parallel relation to said yokestructure and providing support with limited vertical and radialmovement of said power tong unit with respect to said back-up tong unitand to said support yoke.
 5. The positioning apparatus of claim 3,wherein said flexible force transfer means includes chain means anchoredto the lower end of said support column and to said support yoke andsaid force transfer crosshead means includes chain sprocket means. 6.The positioning apparatus of claim 3, wherein said cradle means includesmeans providing resiliently pivoted vertical support of said back-upunit in parallel relation to said yoke structure and providing supportwith limited vertical and radial movement of said rotating unit withrespect to said back-up unit and to said support yoke.
 7. Thepositioning apparatus of claim 3, wherein said power source comprises apiston and cylinder unit having a piston rod connected to said forcetransfer crosshead means.
 8. Th positioning apparatus of claim 7including hydraulic fluid power means for actuating said piston andcylinder unit.
 9. Pipe tong apparatus comprising: a power tong assemblyincluding a pipe back-up tong unit disposed in horizontally parallelrelation with a pipe rotating power tong unit; a vertically disposedsupport column provided with lower bearing means adapted to be mountedto a fixed support in a well derrick and upper bearing means adapted tobe connected to the structure of the derrick to provide vertical andhorizontal support for said column while permitting said column to pivothorizontally; a vertically movable support collar fitted about saidcolumn and supported in alignment for movement up and down said column;a pipe tong support yoke means rigidly mounted to said support collar atits first end to extend horizontally and radially pivotable from saidsupport column; said yoke structure being adapted to receive and supportsaid power tong assembly through a supporting cradle means mounted tothe second end of said yoke; and presser means interposed between saidtong units to apply separating force between said tong units tosubstantiAlly counterbalance the weight of said power tong unit throughvertical movement of said power tong unit, said presser means comprisinga bladder interposed between said tong means, and means for supplyingfluid under pressure to said bladder, said bladder acting on said powertong unit to apply said force.
 10. A pipe tong assembly for making up orbreaking out threaded joints in well pipe comprising a horizontallydisposed back-up tong unit engageable with a vertically disposed, firstthreaded pipe joint part to hold said part and said back-up tong unitagainst rotation and against vertical movement relative to each other,means for supporting said back-up tong unit in a selected verticalposition upon a stationary base, a power tong unit disposed above saidback-up tong unit and engageable with a second complementally threadedpipe joint part that is aligned with said first threaded pipe joint partfor rotating said second threaded pipe joint part into or out ofthreaded engagement with said first threaded pipe joint part whileholding said second threaded pipe joint against vertical movementrelative to said power tong unit, and vertically expandable andcontactible counterbalance means carried by said back-up tong unit andassociated with said power tong unit for yieldably supporting said powertong unit upon said back-up tong unit for vertical movements withrespect to said back-up tong unit, said counterbalance means beingconstructed and arranged to apply an upward force to said power tongunit substantially equal to the weight of said power tong unit as saidpower tong unit is vertically moved in response to the threading of saidsecond threaded pipe joint part into or out of threaded engagement withsaid first threaded pipe joint part, said counterbalance means being thesole means for vertically supporting said power tong unit, saidcounterbalance means comprising a bladder interposed between saidback-up tong unit and said power tong unit, and means for supplyingfluid under pressure to said bladder, said bladder acting on said powertong unit to apply said upward force.
 11. A pipe tong assembly formaking up or breaking out threaded joints in vertically disposed wellpipe comprising: a base member; a back-up tong unit; means for mountingsaid back-up tong unit on said base member and in horizontaldisposition, and for vertical movement and also for horizontal movementwith respect to said base member; a power tong unit; means for mountingsaid power tong unit on and superjacent to said back-up tong unit and inhorizontal disposition, and for limited vertical movements with respectto said back-up tong unit; said back-up tong unit having meansreleasably engageable with a vertically disposed, lower threaded pipejoint part to hold said part and said back-up tong unit against relativerotation and vertical movement therebetween; said power tong unit havingmeans releasably engageable with an upper complementally threaded pipejoint part that is aligned with said lower threaded pipe joint part forrotating said upper threaded pipe joint part into and out of threadedengagement with said lower threaded pipe joint part while holding saidupper pipe joint part and said power tong unit against relative verticalmovement therebetween; counterbalance means including verticallyexpandable and contractible means carried by said back-up tong unit,positioned between said back-up tong unit and said power tong unit, andyieldably supporting said power tong unit for vertical movements withrespect to said back-up tong unit, said counterbalance means beingconstructed and arranged to apply an upward force to said power tongunit substantially equal to the weight thereof as said power tong unitis vertically moved with respect to said back-up tong unit in responseto the threading of said upper threaded pipe joint part into and out ofthreaded enagement with said lower threaded pipe joint part; andconnector means interconnecting said power tong unit and said back-uptong uNit constraining said power tong unit to move horizontally withsaid back-up tong unit as the latter is moved horizontally with respectto said base member.
 12. A pipe tong assembly as defined in claim 11,wherein said means for mounting said back-up tong unit on said basemember includes pivot means having a vertical pivot axis for horizontalpivotal movement of said back-up tong unit with respect to said basemember.
 13. A pipe tong assembly as defined in claim 11, wherein saidvertically expandable and contractible means comprises pneumaticallyexpandable and contractible means.
 14. A pipe tong assembly as definedin claim 11, said vertically expandable and contractible means beingdisposed substantially at the center of gravity of said power tong unit.15. A pipe tong assembly as defined in claim 11, said verticallyexpandable and contractible means comprising a bladder interposedbetween said back-up tong unit and said power tong unit, and means forsupplying fluid under pressure to said bladder, said bladder acting onsaid power tong unit to apply said upward force.
 16. A pipe tongassembly as defined in claim 11, said vertically expandable andcontractible means comprising a piston and cylinder means interposedbetween said back-up tong unit and said power tong unit, said piston andcylinder means acting on said power tong unit to apply said upwardforce.
 17. A pipe tong assembly as defined in claim 11, wherein saidconnector means also constrains said power tong unit to move verticallytowards and away from said back-up tong unit only on parallel planes.18. A pipe tong assembly as defined in claim 17 including keeper meansfor limiting movement of said power tong unit away from said back-uptong unit to a location at which said tong units both engage said jointparts when said joint is to be made up.
 19. A pipe tong assembly asdefined in claim 11, wherein said vertically expandable and contractiblemeans comprises pressure fluid containing means, said counterbalancemeans including a make up pressure regulator and a break out pressureregulator for maintaining selected constant pressures in said pressurefluid containing means and to respectively maintain said upward forceslightly greater than the weight of said power tong unit during themaking up of said joints and slightly less than the weight of said powertong unit during the breaking out of said joints, and means includingselector valve means for selectively communicating said regulators withsaid pressure fluid containing means.
 20. Pipe tong apparatuscomprising: a power tong assembly including a pipe back-up tong unitdisposed in horizontally parallel relation below a pipe rotating powertong unit, presser means interposed between said tong units to applyseparating force between said tong units to substantially counterbalancethe weight of said power tong unit through vertical movement of saidpower tong unit with respect to said back-up tong unit; a verticallydisposed support column provided with lower bearing means adapted to bemounted to a fixed support in a well derrick and upper bearing meansadapted to be connected to the structure of the derrick to providevertical and horizontal support for said column while permitting saidcolumn to pivot horizontally; a vertically movable hollow support collarfitted about said column and supported in alignment for movement up anddown said column by roller means rigidly mounted with said roller andmounted in rolling contact with said column; a pipe tong support yokemeans rigidly mounted to said support collar at its first end to extendhorizontally and radially pivotable from said support column; said yokestructure being adapted to receive and support said power tong assemblythrough a supporting cradle means mounted to the second end of saidyoke; a power source providing linear movement mounted in uprightposition adjacent said column member with its lower end mounted to thelower end of said support column and its upper end connectEd through aflexible force transfer means to said support yoke, said flexible forcetransfer means being anchored relatively between said yoke structure andsaid support column and being connected across a force transfercrosshead means mounted to the upper end of said power source.